Dealership is still researching but they report they had another employee drive a car they had on the lot with DHP. The report: "He couldn't tell the difference on that car either."

So I now have 3 people (one being me) reporting on two different cars that they feel no difference.

Strange.

If you can't feel a difference, how do you even know it's equipped or doing anything?

The entire point of having multiple modes/options is so that you can FEEL a difference. If you can't, they may as well be fake buttons.

At the same time, many people are prone to the placebo effect of their own expectations. This can exaggerate what they believe they notice. A good example is how many people think a sport suspension has dramatically increased their handling ability, while in reality it's actually decreased their car's abilities due to inferior dynamic suspension geometry.

One of my favorite examples of that is sway bars: Often times people like sway bars because they remove body roll and perhaps increases neutrality. And very frequently as well, the installation of the sway bar actually decreases the limits of the car because the tire contact patch is now no longer optimized when the car is loaded.